van overheating

ok heres what i got 1992 e150 5.0 ran great till pulling my boat home i boiled it over ,let it cool added water and drove home ,i have since changed the tstat to a 180, put in new rad. put in new fan clutch,added spring to lower hose ,and the van will run fine with at slow speed but when doing faster than 45 50 it will slowly get hot .van still runs great no smoke no leak ,i can see some flow in raditor thanks

Ford requires at least a 192 degree thermostat to run properly. The computer won't adjust it properly until operating temperature is reached. I have got some bad thermostats and use and old coffee cup boil water and set it in the water if it opens properly I then install it. This will work the system a lot harder.
When its up to temperature it should have good flow through the radiator.
If other items were corroded I would check the pump impeller. Check the fan for any bent or deformed blades. I assume you are not adding any extra anti freeze indicating a blown head gasket.
You didn't replace a towing radiator with a normal one did you? A towing radiator has more capacity.

well im not losing any antifrez and the tstat was checked with boiling water bfore o onstalled it .the new rad was exactly like the one i removed and to be honest the van gets hotter faster after i changed the rad,ther was alot of grit in the old rad and maybe the waterpump has lots of ware
i drove 75 mph for 25 miles last night and it never missed a stroke but is was chillie out side thanks for any thing you got as im out of ideas

The computer system has closed and open loop. Until you reach operating temperature appx. 192 degrees the system will run rich using more fuel its like running with the choke on in an older vehicle. You won't have as much control over timing.
Check base timing unplug the sprout and set to factory specifications. Shut down and plug in the sprout. Timing affects the operating temperature.
I had a man come in with a Chevy S-10 with the thermostat stuck open he claimed low mileage under 8mpg even with cheap fuel about 86 cents a gallon he was aware of it. A new thermostat was installed and it went back to normal appx.16mpg. With the throttle body you could see the flow. Since your buying the fuel its up to you. I was really looking for something else but the scanner said the computer was reading about 140 degrees coolant.
But an engine not timed correctly runs hotter.

well i will check the timing tonight i do have the book that gives me the base timing so i will do that tonight im not sure how i would have gotten off but i will give it a try the van has 97000 on i hate to give it up thans for your help ill let you know

I've been thinking about this do you have good hot heat this would indicate the water pump is good. It would also indicate the air is out of the system.
The only other idea I have is trash in the motor I use a water hose with both radiator hoses and the thermostat removed then I use rags around the water hose stuffed in to the top hose and flush until it runs clear. You indicate springs in both hoses so they don't collapse.

i will try the flush like you said to day,my heat seems to be hot ,and i did flush the heater hoses in both directions when i installed the new raditor,i did put a spring in the lower hose as their wasnt one, i did have an unsual amount of crap in the old rad. lots of scale and what looked like rocks.i bought the rad at a rad shop it looked new to me but im wondering if they just cleaned up a trade in thinking it was ok, and it is auctaly pluged a bit ,i dont know but im getting tierd of monkeing with. Thanks

oh yea i was gonna ask is it possible that the transmission is getting to hot and causing the van to get hot.the other day i drove it 25 to 30 min and it was hot around the l on the ford gauge and when i got off the freeway it cooled to straight up and down after 3 miles at 45 low speed fine high speed not fine

If the flush doesn't work I would try a new radiator. Normally a new unit will come in a box. They may have boiled one out and painted it but they should have run a rod through it and sold it as rebuilt.
If you have a Pep Boys I would check their price and pay for one designed for towing as you pull a boat. They were the closest to what I paid when I had a garage from a distributor.
I thought you brought a brand new one. If a new one solves your problem I would ask for your money back.
I was wondering when you were describing flow as it didn't seem like a new one.
A new one should handle the transmission fine.
Try stopping at the radiator shop and complain before buying a new one as they are aware of what they did and it will make it easier to get your money.